Initial commit: Paperwall, a standalone e-ink dashboard

Navidrome now-playing, clock, and weather for a Waveshare epd4in0e panel,
with a local web UI and install/uninstall scripts for the Pi.

web/templates/index.html

@@ -0,0 +1,25 @@
+{% extends "base.html" %}
+{% block content %}
+<h1>Status</h1>
+
+<img class="preview" src="{{ url_for('static', filename='preview.png') }}?t={{ status.last_render_at }}" alt="preview">
+
+<div class="status-grid">
+  <div>Current screen</div><div>{{ status.current_screen or "-" }}</div>
+  <div>Last render</div><div>{{ status.last_render_at or "-" }}</div>
+  <div>Last panel write</div><div>{{ status.last_display_write_at or "-" }}</div>
+  <div>Navidrome priority</div><div>{{ "on" if navidrome_priority else "off" }}</div>
+  <div>Rotation</div><div>{{ rotation.screens | join(" → ") }} (every {{ rotation.interval_seconds }}s)</div>
+</div>
+
+<div class="actions">
+  <form class="inline" method="post" action="{{ url_for('refresh_now') }}">
+    <button type="submit">Refresh now</button>
+  </form>
+  {% for screen_id, screen in screens.items() %}
+  <form class="inline" method="post" action="{{ url_for('switch_now', screen_id=screen_id) }}">
+    <button class="secondary" type="submit">Show {{ screen.display_name }}</button>
+  </form>
+  {% endfor %}
+</div>
+{% endblock %}